add pg vector and embed

prisma/migrations/20250822104301_init/migration.sql

@@ -0,0 +1,26 @@
+-- Enable pgvector extension
+CREATE EXTENSION IF NOT EXISTS vector;
+
+-- CreateTable
+CREATE TABLE "icd_codes" (
+    "id" TEXT NOT NULL,
+    "code" TEXT NOT NULL,
+    "display" TEXT NOT NULL,
+    "version" TEXT NOT NULL,
+    "category" TEXT NOT NULL,
+    "embedding" vector(1536),
+    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "updatedAt" TIMESTAMP(3) NOT NULL,
+
+    CONSTRAINT "icd_codes_pkey" PRIMARY KEY ("id")
+);
+
+-- Create unique index on code
+CREATE UNIQUE INDEX "icd_codes_code_key" ON "icd_codes"("code");
+
+-- Create ivfflat index for fast vector similarity search
+CREATE INDEX "icd_codes_embedding_idx" ON "icd_codes" USING ivfflat (embedding vector_cosine_ops) WITH (lists = 100);
+
+-- Add comments for documentation
+COMMENT ON COLUMN "icd_codes"."embedding" IS 'Vector embedding for semantic search using pgvector (1536 dimensions)';
+COMMENT ON INDEX "icd_codes_embedding_idx" IS 'IVFFlat index for fast cosine similarity search with 100 lists';